As most circumstellar nebulae around evolved massive
stars have been observed in
the (near)-infrared waveband, we consequently desire, in order
to discuss our models in the context of real data, to know how our simulated
objects would look like if observed at that particular waveband.
We perform radiative transfer calculations of our MHD simulation outputs against
dust opacity using the radmc-3d code [1]}. Dust density fields
are constructed by assuming a standard gas-to-dust ratio of \(1/200\)  and it is imported
into radmc-3d. The dust temperature is simulated by Monte-Carlo calculation
using the algorithm of [2]} and photon packages are ray-traced
from the stellar atmosphere to the stellar wind nebulae. The \(24\, \mu \rm m\)  near-infrared
emissivity is estimated using the Silicates dust opacity of [3]}
and it is projected onto the plane of the sky according to a particular selected
viewing angle.
The irradiating central massive star is assumed to be a spherical black body
radiator of effective temperature \(T_{\rm eff}\)  that is taken as,
\(T_{\rm eff}(t) = \Bigg \lbrace \begin{array}{lll}T_{\rm eff}^{\rm bsg} & \mathrm {if} & t \le t_{\rm wr}-\Delta t , \\\Delta T_{\rm eff}(1-F) + T_{\rm eff}^{\rm wr} & \mathrm {if} & t_{\rm wr}-\Delta t < t and t \le t_{\rm wr}, \\T_{\rm eff}^{\rm wr} & \mathrm {if} & t_{\rm wr} < t, \\\end{array}\) 
